Why it’s great to have a geologist in the house

Science has a way of surprising us when we least expect it. Like with mud rocks.

We science journalists can be a cranky lot, eternally skeptical as to whether a touted advance is really significant enough to warrant coverage. So when Science News’ managing editor Erin Wayman waxed enthusiastic about a study explaining how ancient plants may have played a key role in making Earth muddier, I perked up.

Geologists have long known that mud started to take hold at some point, but as earth and climate writer Carolyn Gramling reports in this issue, “no one had ever pinpointed when that muddening happened.”

Clearly erosion must have been a factor, but that’s as far as my mud expertise goes. A geologist I am not. Fortunately, Gramling is a geologist, with bachelor’s degrees in both geology and European history and a Ph.D. in marine geochemistry. I asked her what it was about this study that convinced her it was worth a look. “It struck me because I like to know what makes things tick,” she said during a conversation in my office. “It was surprising.”

This wasn’t a big sexy science story: no neutron star collisions, no gene-editing breakthroughs, no advances in immunotherapy. Instead, we have grayish rocks. But they have something to tell us. The researchers, at the University of Cambridge, looked at ancient riverbed deposits and found that the amount of mud rock, which is primarily made of clay, silt and other fine particles, increased about 458 million years ago. That’s also when a group of primitive land plants known as bryophytes, which include modern mosses and liverworts, became common on Earth.

The fact that bryophytes could have had that much impact is another surprise, Gramling said. “These are not rooted plants,” she added. “They’re these little mats of mosses on the surface, but they still have this profound effect.” Indeed, the author of a commentary accompanying the study in Science called the plants “tiny, little scrappy things.”

I like the notion of scrappy little underdog plants helping to transform the face of our planet. And I very much like having a writer on staff who’s a scientist with deep expertise who can say, yes, this is as neat as it sounds.

Gramling was quick to note that we don’t know exactly how ancient plants made Earth muddier. But even simple plants can help keep wind and water from eroding sediments. Plants may also help break down rock chemically, too.

Mud is often the bane of gardeners. But as this spring blooms, it wouldn’t be out of place to offer a nod of thanks to the scrappy little ancient plants who helped make mud happen.